Organic compounds, methods for their preparation, organic solar cell acceptor materials, solar cells

Abstract

The application discloses an organic compound and a preparation method thereof, an organic solar cell acceptor material, and a solar cell. The chemical structural formula of the organic compound is shown in the description. The organic compound is a brand-new non-fullerene acceptor molecule, and the charge mobility is improved by improving the regional flatness of the central core.

Description

Technical Field

[0001] This invention relates to the field of organic semiconductor materials technology, and more specifically, to an organic compound and its preparation method, an organic solar cell acceptor material, and a solar cell. Background Technology

[0002] With economic development and the increasing prominence of energy crises and environmental pollution, humanity must develop and utilize new renewable energy sources. Solar energy, as an inexhaustible and clean energy source, is the best alternative to fossil fuels.

[0003] Solar cells are highly efficient solar energy utilization devices, achieving photoelectric conversion using the photovoltaic effect of organic semiconductors. Among the various types of solar cells fabricated by scientists, organic solar cells have significant advantages: low cost, high flexibility, environmental friendliness, simple processing, and the ability to be printed to fabricate flexible devices.

[0004] Currently, the core component of organic solar cells is the active layer, which is prepared by blending donor and acceptor materials. The active layer is primarily responsible for converting photons into electrical charges and transporting these charges to the interface, enabling them to reach the electrodes and generate current. In early research, fullerene derivatives dominated; however, their drawbacks limited the development of solar cells, such as difficulty in energy level tuning and weak absorption in the visible light region. In recent years, more and more researchers have focused on developing non-fullerene acceptor materials. The successful development of non-fullerene acceptor materials benefits from their advantages, such as ease of energy level tuning, strong and wide absorption in the visible light region, and ease of synthesis and purification. In the past five years, organic solar cells have experienced rapid development due to the development of non-fullerene acceptors.

[0005] Currently, the most efficient non-fullerene acceptors are mainly electron-withdrawing-electron-donating-electron-withdrawing (ADA) type non-fullerene acceptors. Recent research shows that introducing electron-withdrawing groups (such as benzothiadiazole) into the D-unit conjugated framework can modulate the energy levels of the acceptor material and enhance intermolecular forces, thereby improving photon utilization. However, enhanced intermolecular forces are detrimental to efficient light emission because the aggregated excimers can lead to changes in the emission spectrum and a decrease in fluorescence quantum yield, which in turn increases nonradiative recombination and reduces photoelectric conversion efficiency. Summary of the Invention

[0006] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide an organic compound and its preparation method, an organic solar cell acceptor material, and a solar cell. By developing non-fullerene acceptor molecules through new molecular synthesis design, the photoelectric conversion efficiency of organic solar cells can be improved.

[0007] To achieve the above objectives, the first technical solution of the present invention is as follows:

[0008] An organic compound with the chemical structure shown in Formula 1:

[0009]

[0010] R1 is independently selected from C1 to C30 alkyl, C1 to C30 haloalkyl, C1 to C30 alkoxy, C1 to C30 alkylthio or C4 to C30 aryl;

[0011] X1, X2, X3, and X4 are each independently selected from H, halogen substituents, trifluoromethyl, cyano, ester, C1-C30 alkyl, C1-C30 haloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, or C4-C30 aryl.

[0012] Ar is independently selected from thiophene group, thiophene derivative group, bis(thiophene) group, bis(thiophene) derivative group, tri(thiophene) group, tri(thiophene) derivative group, benzo(thiophene) group, benzo(thiophene) derivative group, pyrrolo(thiophene) group, pyrrolo(thiophene) derivative group, pyrrolo(diphenyl) group, pyrrolo(diphenyl) derivative group, pentane(thiophene) group, pentane(thiophene) derivative group, pentane(diphenyl) group or pentane(diphenyl) derivative group;

[0013] Each EG group is independently selected from any one of the following groups:

[0014]

[0015] R4 is selected from hydrogen atom, halogen substituent, C1-C20 alkyl, C1-C20 alkoxy, carbonyl, ester or cyano groups.

[0016] The second technical solution of the present invention is as follows:

[0017] A method for preparing the above-mentioned organic compound includes the following steps:

[0018] Compound X and compound A are coupled via a Stille reaction to yield compound B. The chemical reaction equation is as follows:

[0019]

[0020] Compound B undergoes a cyclization reaction with compound C to yield compound D, and the chemical reaction equation is as follows:

[0021]

[0022] Compound D undergoes a ring-closing reaction to yield compound E, and the chemical reaction equation is as follows:

[0023]

[0024] Compound E reacts with a haloalkane via a nucleophilic substitution reaction to yield compound F, wherein the haloalkane is R1X, and X is a halogen; the chemical reaction equation is as follows:

[0025]

[0026] Compound F is reacted with Vilsmeier-Haack to yield compound G, and the chemical reaction equation is as follows:

[0027]

[0028] The compounds G and EG were reacted via a Knoevenagel reaction to yield an organic compound as shown in Formula 1.

[0029] The third technical solution of the present invention is as follows:

[0030] An organic solar cell acceptor material comprising the aforementioned organic compound.

[0031] The fourth technical solution of the present invention is as follows:

[0032] A solar cell includes a photoelectric conversion active layer, the photoelectric conversion active layer comprising an organic solar cell electron donor material and the aforementioned organic solar cell acceptor material.

[0033] Implementing the embodiments of the present invention will have the following beneficial effects:

[0034] The organic compound of this invention comprises a fused-ring benzodipyrrolodioxin central core with a benzo-nitrogen-bridged heterocyclic "T"-shaped fused ring structure and electron-withdrawing terminal groups EG connected to both ends of the central core. It is also modified with alkane chains or alkoxy chains. The fused-ring benzodipyrrolodioxin central core unit connects benzodioxin to the conjugated group via nitrogen atoms. The lone pair of electrons from the nitrogen atom participates in conjugation, increasing the electron cloud density of the conjugated system and improving the electron-donating ability of the central core. Simultaneously, the introduction of an alkyl chain R1 onto the nitrogen atom not only increases the regional flatness of the central core, potentially improving charge mobility, but also further improves the solubility of the organic compound. The simultaneous introduction of electron-withdrawing terminal groups EG at both ends of the fused-ring benzodipyrrolodioxin central core unit effectively broadens the absorption coefficient of the material.

[0035] The organic compounds of this invention exhibit good solubility, are easily processed into films, possess strong visible and near-infrared absorption properties, and have high charge mobility (≥10). -4 cm 2 ·V -1·s -1 These materials can be used to prepare solar cell materials with high short-circuit current and energy conversion efficiency, and are a class of promising acceptor materials.

[0036] Compared with previous fullerenes and their derivatives, the organic compounds of this invention can regulate energy levels, have good film-forming properties, and have high photoelectric conversion efficiency. The finished products can be made into flexible solar panels.

[0037] The organic compounds of this invention have mild synthesis conditions and are inexpensive, which is conducive to large-scale production. Attached Figure Description

[0038] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] in:

[0040] Figure 1 This is a synthetic route diagram of organic compound X1 in Example 1 of the present invention.

[0041] Figure 2 This is a cyclic voltammetry curve of the organic compound X1 obtained in Example 1 of this invention.

[0042] Figure 3 This is a synthetic route diagram of organic compound X2 in Example 3 of the present invention.

[0043] Figure 4 This is a cyclic voltammetry curve of the organic compound X2 obtained in Example 3 of this invention.

[0044] Figure 5 This is the synthetic route diagram of organic compound X3 in Example 5 of the present invention.

[0045] Figure 6 This is a cyclic voltammetry curve of the organic compound X3 obtained in Example 5 of this invention. Detailed Implementation

[0046] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] This invention discloses an organic compound whose chemical structure is shown in Formula 1:

[0048]

[0049]

[0050] Each of R1 is independently selected from C1-C30 alkyl, C1-C30 haloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, or C4-C30 aryl. Preferably, each of R1 is independently selected from C1-C20 alkyl, C1-C20 haloalkyl, C1-C20 alkoxy, C1-C20 alkylthio, or C4-C20 aryl. More preferably, each of R1 is independently selected from C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 alkylthio, or C4-C12 aryl.

[0051] X1, X2, X3, and X4 are each independently selected from H, halogen substituents, trifluoromethyl, cyano, ester, C1-C30 alkyl, C1-C30 haloalkyl, C1-C30 alkoxy, C1-C30 alkylthio, or C4-C30 aryl. Preferably, X1, X2, X3, and X4 are each independently selected from H, halogen substituents, trifluoromethyl, cyano, C1-C20 alkyl, C1-C20 haloalkyl, C1-C20 alkoxy, C1-C20 alkylthio, or C4-C20 aryl. More preferably, X1, X2, X3, and X4 are each independently selected from H, halogen substituents, trifluoromethyl, cyano, C1-C12 alkyl, C1-C12 haloalkyl, C1-C12 alkoxy, C1-C12 alkylthio, or C4-C12 aryl.

[0052] Ar is independently selected from thiophene groups, thiophene derivative groups, bis(thiophene) groups, bis(thiophene) derivative groups, tri(thiophene) groups, tri(thiophene) derivative groups, benzo(thiophene) groups, benzo(thiophene) derivative groups, pyrrolo(thiophene) groups, pyrrolo(thiophene) derivative groups, pyrrolo(diphenyl) groups, pyrrolo(diphenyl) derivative groups, pentane(thiophene) groups, pentane(thiophene) derivative groups, pentane(diphenyl) groups, or pentane(diphenyl) derivative groups. In the above technical solutions, when Ar is selected from derivative groups, it refers to the presence of some common substituent groups in the main structure, such as C1-C20 alkyl groups, C1-C20 alkoxy groups, carbonyl groups, ester groups (such as C1-C20 alkoxy acyl groups), phenyl groups, substituted phenyl groups (the benzene ring mainly contains C1-C20 alkyl groups or C1-C20 alkoxy groups), thiophene groups, or substituted thiophene groups (the thiophene ring mainly contains C1-C20 alkyl groups or C1-C20 alkoxy groups), etc.

[0053] Preferably, each Ar group is independently selected from any one of the following groups, with the dotted lines indicating the connection positions:

[0054]

[0055] R3 is independently selected from C1-C20 alkyl, C1-C20 alkoxy, carbonyl, ester (preferably C1-C20 alkoxyacyl), phenyl, substituted phenyl (preferably substituted phenyl contains at least one C1-C20 alkyl and / or C1-C20 alkoxy, most preferably contains one C1-C20 alkyl or C1-C20 alkoxy), thiophene or substituted thiophene (preferably substituted thiophene contains at least one C1-C20 alkyl and / or C1-C20 alkoxy, most preferably contains one C1-C20 alkyl or C1-C20 alkoxy).

[0056] Each EG group is independently selected from any one of the following groups, with the dotted lines indicating the connection positions:

[0057]

[0058] R4 is selected from hydrogen atom, halogen substituent (halogen substituent is fluorine, chlorine, bromine or iodine), C1 to C20 alkyl, C1 to C20 alkoxy, carbonyl, ester (such as C1 to C20 alkoxyacyl) or cyano.

[0059] The organic compound of the present invention comprises a fused-ring benzodipyrrolodioxin central core with a benzo-nitrogen-bridged heterocyclic "T"-shaped fused ring structure and electron-withdrawing terminal groups EG connected to both ends of the central core. It is also modified with alkane chains or alkoxy chains. The fused-ring benzodipyrrolodioxin central core unit connects benzodioxin to the conjugated group through nitrogen atoms. The lone pair of electrons of the nitrogen atom participates in conjugation, increasing the electron cloud density of the conjugated system and improving the electron-donating ability of the central core. At the same time, the introduction of alkyl chains R1 on the nitrogen atoms can not only increase the regional flatness of the central core, thereby potentially improving the charge mobility, but also further improve the solubility of the organic compound. The simultaneous introduction of electron-withdrawing terminal groups EG at both ends of the fused-ring benzodipyrrolodioxin central core unit can effectively broaden the absorption coefficient of the material.

[0060] The organic compounds of this invention exhibit good solubility, are easily processed into films, possess strong visible and near-infrared absorption properties, and have high charge mobility (≥10). -4 cm 2 ·V -1 ·s -1 These materials can be used to prepare solar cell materials with high short-circuit current and energy conversion efficiency, and are a class of promising acceptor materials.

[0061] Compared with previous fullerenes and their derivatives, the organic compounds of this invention can regulate energy levels, have good film-forming properties, and have high photoelectric conversion efficiency. The finished products can be made into flexible solar panels.

[0062] The present invention also discloses a method for preparing the above-mentioned organic compound, comprising the following steps:

[0063] 1) Compound X and compound A are coupled via a Stille coupling reaction to yield compound B. The chemical reaction equation is as follows:

[0064]

[0065] 2) Compound B undergoes a cyclization reaction with compound C to give compound D. The chemical reaction equation is as follows:

[0066]

[0067] 3) Compound D undergoes a ring-closing reaction to give compound E. The chemical reaction equation is as follows:

[0068]

[0069] 4) Compound E reacts with a haloalkane via a nucleophilic substitution reaction to give compound F, where the haloalkane is R1X, and X is a halogen; the chemical reaction equation is as follows;

[0070]

[0071] 5) Compound F is reacted with Vilsmeier-Haack to give compound G, and the chemical reaction equation is as follows;

[0072]

[0073] 6) Compounds G and EG reacted via the Knoevenagel reaction to give an organic compound as shown in Formula 1.

[0074] Specifically, the conditions for the Stille coupling reaction are as follows: the solvent is toluene, the catalyst is tetrakis(triphenylphosphine)palladium, and the amount of catalyst added is 0.01% to 10% of the molar amount of compound A; the molar ratio of compound X to compound A is 1:2.2 to 3.5; and the reaction is carried out under reflux at 80℃ to 110℃ for 24 to 48 hours.

[0075] The conditions for the above cyclization reaction are as follows: the solvent is N,N-dimethylformamide, the neutralizing agent is potassium carbonate, the molar ratio of the neutralizing agent to compound B is 1 to 20:1, and the reaction is carried out under reflux at 80°C to 120°C for 0.1 to 1 hour.

[0076] The conditions for the above ring-closure reaction are as follows: the solvent is o-dichlorobenzene, the catalyst is triphenylphosphine, the molar ratio of the catalyst to compound C is 1:1 to 20, and the reaction is carried out under reflux at 150℃ to 200℃ for 12 hours.

[0077] The conditions for the above nucleophilic substitution reaction are as follows: N,N-dimethylformamide is used as the solvent, potassium hydroxide is used as the neutralizing agent, and the molar ratio of haloalkanes to compound E is 3 to 6:1; the reaction is carried out under reflux at 80°C to 100°C for 15 to 24 hours.

[0078] The conditions for the above Vilsmeier-Haack reaction are as follows: the solvent is N,N-dimethylformamide, phosphorus oxychloride is the formylation reagent, the molar ratio of compound E to phosphorus oxychloride is 1:15-25, and the reaction is carried out under reflux at 80℃-105℃ for 8-12 hours.

[0079] The conditions for the above Knoevenagel reaction are: chloroform as solvent, pyridine as acid-binding agent, and the molar ratio of compound E to EG is 1:5 to 12; the reaction is carried out under reflux at 60℃ to 70℃ for 12 to 16 hours.

[0080] In summary, the organic compounds of this invention have mild synthesis conditions and are inexpensive, which is conducive to large-scale production.

[0081] The present invention also provides an organic solar cell acceptor material comprising the above-mentioned organic compounds.

[0082] The present invention also provides a solar cell, including a photoelectric conversion active layer, wherein the photoelectric conversion active layer comprises the organic solar cell acceptor material as described above.

[0083] In one specific embodiment, the electron donor material of the organic solar cell includes one or more of PM6 (CAS No.: 1802013-83-7), D18 (CAS: 2230218-36-5), PBDB-T (CAS: 145929-80-4), and PTB7-Th (CAS: 1469791-66-9).

[0084] In one specific embodiment, the molar ratio of organic solar cell acceptor material to organic solar cell electron donor material is 1 to 1.5:1.

[0085] The following are specific embodiments.

[0086] Example 1

[0087] The chemical structural formula of organic compound X1 is:

[0088]

[0089] refer to Figure 1 Its preparation method includes the following steps:

[0090] (1) Compound 2 and compound 1 are coupled via a Stille coupling reaction to give compound 3:

[0091]

[0092] Compound 1 (362 mg, 1 mmol), compound 2 (1.283 g, 2.2 mmol), and Pd(PPh3)Cl2 (43.5 mg, 0.06 mmol) were dissolved in 10 mL of dry toluene and stirred overnight at 110 °C. The reaction mixture was cooled to room temperature and then concentrated under reduced pressure. Chromatographic purification was performed on a silica gel column using dichloromethane / petroleum ether (1 / 3, v / v) as eluent to give compound 3 as a yellow solid (552 mg, 71% yield).

[0093] (2) Compound 3 undergoes a cyclization reaction with tetrafluoro-o-diphenol and potassium carbonate under nitrogen protection to give compound 4:

[0094]

[0095] K₂CO₃ (294 mg, 3 mmol) was added to an anhydrous DMF (5.0 mL) solution of tetrafluorocatechol (364 mg, 2 mmol) under nitrogen atmosphere. After stirring at room temperature for 0.5 hours, compound 3 (789 mg, 1 mmol) was added to the mixture. After stirring at 80 °C for 15 min, the reaction was quenched with water and extracted three times with CH₂Cl₂. The organic layer was concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel) using CH₂Cl₂:petroleum ether (1:3) as eluent to give compound 4 as a yellow solid (763 mg, 82%).

[0096] (3) Compound 4 reacts with triethyl phosphite and o-dichlorobenzene in a ring-closing reaction to give compound 5:

[0097]

[0098] PPh3 (5.13 g, 19.55 mmol) was added to a solution of compound 4 (931 mg, 1 mmol) in ODCB (8.5 mL) under nitrogen atmosphere. The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was rapidly passed through a silica gel column using CH2Cl2 as the eluent. A crude cyclized product, compound 5, was obtained as a deep red solid. To avoid oxidation, the crude product was not further purified.

[0099] (4) Compound 5 reacts with potassium carbonate under nitrogen protection to undergo alkylation to obtain compound 6:

[0100]

[0101] Compound 5 was mixed with K₂CO₃ (348 mg, 2.52 mmol), KI (418 mg, 2.52 mmol), 1-bromo-2-ethylhexane (486 mg, 2.52 mmol), and anhydrous DMF (4.0 mL). Under nitrogen atmosphere, the mixture was stirred at 100 °C for 1 hour. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure, and the crude product was purified by column chromatography (silica gel) using CH₂Cl₂:petroleum ether (1:5) as eluent to give the alkylated product as a black oil. To avoid oxidation, the alkylated product was rapidly mixed with anhydrous DMF (0.1 mL), POCl₃ (0.1 mL), and dichloroethane (5.0 mL) at 0 °C under nitrogen atmosphere. After stirring at room temperature for 10 min, the mixture was heated to 80 °C and stirred for 1 hour. The reaction was quenched with a saturated KOAc aqueous solution and stirred at room temperature for 15 min. The organic layer was concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel) using CH2Cl2:petroleum ether (1:1) as eluent to give compound 5 as a yellow solid (286.9 mg, 25%).

[0102] (5) Compound 6 was given to compound 7 via the Vilsmeier-Haack reaction;

[0103]

[0104] POCl3 (0.3 mL) and DMF (3 mL) were added to a three-necked round-bottom flask and stirred at 0 °C for 2 h under nitrogen protection. Then, compound (6) (0.15 g, 0.16 mmol) was added to a 1,2-dichloroethane solution (5 mL). After stirring at 80 °C for 12 h, the mixture was quenched with saturated CH3COONa(aq) and extracted with dichloromethane (2 x 10 mL). The organic phase was dried over anhydrous MgSO4 and filtered. After removing the solvent from the filtrate, the mixture was purified by column chromatography on silica gel using petroleum ether / dichloromethane (3:1) as the eluent to give an orange solid (0.13 g, 84% yield).

[0105] (7) Compounds 7 and 5,6-difluoro-3-(dicyanomethylene)indoline ketone were used to obtain X1 receptor materials via the Knoevenagel reaction:

[0106]

[0107] A solution of compound 7 (1147.6 mg, 1 mmol) and 2-(5,6-difluoro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (1142 mg, 5 mmol) was added under nitrogen atmosphere with 5.0 mL of CHCl3 and 0.2 mL of pyridine. The reaction mixture was heated to reflux and stirred for 1.5 hours. After cooling to room temperature, the mixture was purified by column chromatography (silica gel) using CHCl3 as the eluent to give X1 (1273 mg, 81%) as a dark blue solid. 1H NMR (400MHz, CDCl3): δ7.64(t,J=7.6Hz,2H),7.06-6.99(m,4H),4.66(d,J=8.0Hz,4H),3.23(t,J=8.0Hz,4H),2.19-2.05(m,2 H),1.93-1.81(m,4H),1.57-1.49(m,4H),1.42-0.95(m,44H),0.90-0.83(m,6H),0.81(q,J=7.4Hz,6H),0.72(q,J=7.5Hz,6H).

[0108] The cyclic voltammetry curve of X1 is as follows: Figure 2 As shown, its HOMO energy level is -5.71 eV, its LUMO energy level is -3.84 eV, and its band gap is 1.87 eV, indicating that the organic compound shown in Formula 1 has good electron accepting ability and can match the energy levels of most common electron donor materials.

[0109] Example 2

[0110] Fabrication of solar cells.

[0111] The indium tin oxide (ITO) glass used as the cathode (purchased from Shenzhen Nanbo Float Glass Co., Ltd.) was first cleaned with detergent, then ultrasonically cleaned with deionized water, acetone, and isopropanol in sequence. After drying, a 30nm thick PEDOT:PSS anode modification layer was spin-coated and dried at 150℃ for 15 minutes for later use.

[0112] 0.8 mg of the organic compound X1 prepared in Example 1 and 0.7 mg of the polymer donor material PM6 were mixed in 0.1 mL of chloroform to obtain a mixture, which was then spin-coated onto the above PEDOT:PSS layer. After drying, a light-harvesting active layer (effective area of ​​4 mm²) was obtained. 2 A 5 nm thick PDINN cathode modification layer was spin-coated onto the active layer under vacuum (absolute pressure 2 × 10⁻⁶). -5 A metallic Ag of approximately 80 nm is deposited by vapor deposition (Pa) as the cathode of a solar cell.

[0113] A simulated solar light source was used with an AM1.5 filter (SAN-EI ELECTRIC Co., Ltd. model XES-70S1), at 100mW / cm². 2 Photocurrent density was measured under varying light intensity, calibrated using a standard monocrystalline silicon solar cell (purchased from VLSI Standards Inc.). Dark current density was also measured in the dark state. The resulting IV curves were measured using a Keithley 2450 Source-Measure Unit, controlled by a computer via LabVIEW software. The resulting IV curves are shown below. Figure 2 As shown, a battery capable of generating current can be formed.

[0114] Table 1 lists the performance parameters of the solar cells at different ratios of PM6 and X1, two materials in the active layer.

[0115] Table 1: Performance parameters of PM6 and X1 batteries using two materials

[0116]

[0117] Example 3

[0118] The chemical structural formula of organic compound X2 is:

[0119]

[0120] refer to Figure 3 Its preparation method includes the following steps:

[0121] (1) Compound 2 and compound 1 are coupled via a Stille coupling reaction to give compound 3:

[0122]

[0123] Compound 1 (362 mg, 1 mmol), compound 2 (1.223 g, 2.2 mmol), and Pd(PPh3)Cl2 (43.5 mg, 0.06 mmol) were dissolved in 10 mL of dry toluene and stirred overnight at 110 °C. The reaction mixture was cooled to room temperature and then concentrated under reduced pressure. Chromatographic purification was performed on a silica gel column using dichloromethane / petroleum ether (1 / 3, v / v) as eluent to give compound 3 as a yellow solid (575 mg, 71% yield).

[0124] (2) Compound 3 undergoes a cyclization reaction with tetrafluoro-o-diphenol and potassium carbonate under nitrogen protection to give compound 4:

[0125]

[0126] K₂CO₃ (294 mg, 3 mmol) was added to an anhydrous DMF (5.0 mL) solution of tetrafluorocatechol (364 mg, 2 mmol) under nitrogen atmosphere. After stirring at room temperature for 0.5 hours, compound 3 (705 mg, 1 mmol) was added to the mixture. After stirring at 80 °C for 15 min, the reaction was quenched with water and extracted three times with CH₂Cl₂. The organic layer was concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel) using CH₂Cl₂:petroleum ether (1:3) as eluent to give compound 4 as a yellow solid (745 mg, 85%).

[0127] (3) Compound 4 reacts with triethyl phosphite and o-dichlorobenzene in a ring-closing reaction to give compound 5:

[0128]

[0129] PPh3 (5.13 g, 19.55 mmol) was added to a solution of compound 4 (847 mg, 1 mmol) in ODCB (8.5 mL) under nitrogen atmosphere. The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was rapidly passed through a silica gel column using CH2Cl2 as the eluent. A crude cyclized product, compound 5, was obtained as a deep red solid. To avoid oxidation, the crude product was not further purified.

[0130] (4) Compound 5 reacts with potassium carbonate under nitrogen protection to undergo alkylation to obtain compound 6:

[0131]

[0132] Compound 5 was mixed with K₂CO₃ (348 mg, 2.52 mmol), KI (418 mg, 2.52 mmol), 1-bromo-2-ethylhexane (486 mg, 2.52 mmol), and anhydrous DMF (4.0 mL). Under nitrogen atmosphere, the mixture was stirred at 100 °C for 1 hour. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure, and the crude product was purified by column chromatography (silica gel) using CH₂Cl₂:petroleum ether (1:5) as eluent to give the alkylated product as a black oil. To avoid oxidation, the alkylated product was rapidly mixed with anhydrous DMF (0.1 mL), POCl₃ (0.1 mL), and dichloroethane (5.0 mL) at 0 °C under nitrogen atmosphere. After stirring at room temperature for 10 min, the mixture was heated to 80 °C and stirred for 1 hour. The reaction was quenched with a saturated KOAc aqueous solution and stirred at room temperature for 15 min. The organic layer was concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel) using CH2Cl2:petroleum ether (1:1) as eluent to give compound 5 as a yellow solid (273.6 mg, 23%).

[0133] (5) Compound 6 was given to compound 7 via the Vilsmeier-Haack reaction;

[0134]

[0135] POCl3 (0.3 mL) and DMF (3 mL) were added to a three-necked round-bottom flask and stirred at 0 °C for 2 h under nitrogen protection. Then, compound (6) (0.15 g, 0.16 mmol) was added to a 1,2-dichloroethane solution (5 mL). After stirring at 80 °C for 12 h, the mixture was quenched with saturated CH3COONa(aq) and extracted with dichloromethane (2 x 10 mL). The organic phase was dried over anhydrous MgSO4 and filtered. After removing the solvent from the filtrate, the mixture was purified by column chromatography on silica gel using petroleum ether / dichloromethane (3:1) as the eluent to give an orange solid (0.13 g, 84% yield).

[0136] (7) Compounds 7 and 5,6-dichloro-3-(dicyanomethylene)indoline ketone were used to obtain X2 acceptor materials via the Knoevenagel reaction:

[0137]

[0138] A solution of compound 7 (1136.6 mg, 1 mmol) and 2-(5,6-dichloro-3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (1142 mg, 5 mmol) was added under nitrogen atmosphere with 5.0 mL of CHCl3 and 0.2 mL of pyridine. The reaction mixture was heated to reflux and stirred for 1.5 hours. After cooling to room temperature, the mixture was purified by column chromatography (silica gel) using CHCl3 as the eluent to give X2 (1273 mg, 81%) as a dark blue solid. 1H NMR (400MHz, CDCl3): δ7.62(t,J=7.6Hz,2H),7.02-6.99(m,4H),4.46(d,J=8.0Hz,4H),3.03(t,J=8.0Hz,4H),2.18-2.03(m,2 H),1.90-1.80(m,4H),1.43-1.37(m,4H),1.42-0.90(m,32H),0.90-0.83(m,6H),0.81(q,J=7.4Hz,6H),0.72(q,J=7.5Hz,6H).

[0139] Example 4

[0140] Fabrication of solar cells.

[0141] The indium tin oxide (ITO) glass used as the cathode (purchased from Shenzhen Nanbo Float Glass Co., Ltd.) was first cleaned with detergent, then ultrasonically cleaned with deionized water, acetone, and isopropanol in sequence. After drying, a 30nm thick PEDOT:PSS anode modification layer was spin-coated and dried at 150℃ for 15 minutes for later use.

[0142] 0.8 mg of the organic compound X2 prepared in Example 1 and 0.7 mg of the polymer donor material PM6 were mixed in 0.1 mL of chloroform to obtain a mixture, which was then spin-coated onto the above PEDOT:PSS layer. After drying, a light-harvesting active layer (effective area of ​​4 mm²) was obtained. 2 A 5 nm thick PDINN cathode modification layer was spin-coated onto the active layer under vacuum (absolute pressure 2 × 10⁻⁶). -5 A metallic Ag of approximately 80 nm is deposited by vapor deposition (Pa) as the cathode of a solar cell.

[0143] A simulated solar light source was used with an AM1.5 filter (SAN-EI ELECTRIC Co., Ltd. model XES-70S1), at 100mW / cm². 2 Photocurrent density was measured under varying light intensity, calibrated using a standard monocrystalline silicon solar cell (purchased from VLSI Standards Inc.). Dark current density was also measured in the dark state. The resulting IV curves were measured using a Keithley 2450 Source-Measure Unit, controlled by a computer via LabVIEW software. The resulting IV curves are shown below. Figure 4 As shown, a battery capable of generating current can be formed.

[0144] Table 2 lists the performance parameters of the solar cells with different ratios of PM6 and X2 materials in the active layer.

[0145] Table 2: Performance parameters of PM6 and X1 batteries using two materials

[0146]

[0147] Example 5

[0148] The chemical structural formula of organic compound X3 is:

[0149]

[0150] refer to Figure 5 Its preparation method includes the following steps:

[0151] (1) Compound 2 and compound 1 are coupled via a Stille coupling reaction to give compound 3:

[0152]

[0153] Compound 1 (362 mg, 1 mmol), compound 2 (1.252 g, 2.2 mmol), and Pd(PPh3)Cl2 (43.5 mg, 0.06 mmol) were dissolved in 10 mL of dry toluene and stirred overnight at 110 °C. The reaction mixture was cooled to room temperature and then concentrated under reduced pressure. Chromatographic purification was performed on a silica gel column using dichloromethane / petroleum ether (1 / 3, v / v) as eluent to give compound 3 as a yellow solid (585 mg, 76% yield).

[0154] (2) Compound 3 undergoes a cyclization reaction with tetrafluoro-o-diphenol and potassium carbonate under nitrogen protection to give compound 4:

[0155]

[0156] K₂CO₃ (294 mg, 3 mmol) was added to an anhydrous DMF (5.0 mL) solution of tetrafluorocatechol (364 mg, 2 mmol) under nitrogen atmosphere. After stirring at room temperature for 0.5 hours, compound 3 (761 mg, 1 mmol) was added to the mixture. After stirring at 80 °C for 15 min, the reaction was quenched with water and extracted three times with CH₂Cl₂. The organic layer was concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel) using CH₂Cl₂:petroleum ether (1:3) as eluent to give compound 4 as a yellow solid (720 mg, 81%).

[0157] (3) Compound 4 reacts with triethyl phosphite and o-dichlorobenzene in a ring-closing reaction to give compound 5:

[0158]

[0159] PPh3 (5.13 g, 19.55 mmol) was added to a solution of compound 4 (903 mg, 1 mmol) in ODCB (8.5 mL) under nitrogen atmosphere. The reaction mixture was heated to reflux and stirred overnight. After cooling to room temperature, the mixture was rapidly passed through a silica gel column using CH2Cl2 as the eluent. A crude cyclized product, compound 5, was obtained as a deep red solid. To avoid oxidation, the crude product was not further purified.

[0160] (4) Compound 5 reacts with potassium carbonate under nitrogen protection to undergo alkylation to obtain compound 6:

[0161]

[0162] Compound 5 was mixed with K₂CO₃ (348 mg, 2.52 mmol), KI (418 mg, 2.52 mmol), 1-bromo-2-ethylhexane (486 mg, 2.52 mmol), and anhydrous DMF (4.0 mL). Under nitrogen atmosphere, the mixture was stirred at 100 °C for 1 hour. After cooling to room temperature, the reaction was quenched with water and extracted three times with petroleum ether. The organic layer was concentrated under reduced pressure, and the crude product was purified by column chromatography (silica gel) using CH₂Cl₂:petroleum ether (1:5) as eluent to give the alkylated product as a black oil. To avoid oxidation, the alkylated product was rapidly mixed with anhydrous DMF (0.1 mL), POCl₃ (0.1 mL), and dichloroethane (5.0 mL) at 0 °C under nitrogen atmosphere. After stirring at room temperature for 10 min, the mixture was heated to 80 °C and stirred for 1 hour. The reaction was quenched with a saturated KOAc aqueous solution and stirred at room temperature for 15 min. The organic layer was concentrated under reduced pressure. The crude product was purified by column chromatography (silica gel) using CH2Cl2:petroleum ether (1:1) as eluent to give compound 5 as a yellow solid (278 mg, 21%).

[0163] (5) Compound 6 was given to compound 7 via the Vilsmeier-Haack reaction;

[0164]

[0165] POCl3 (0.3 mL) and DMF (3 mL) were added to a three-necked round-bottom flask and stirred at 0 °C for 2 h under nitrogen protection. Then, compound (6) (0.12 g, 0.13 mmol) was added to a 1,2-dichloroethane solution (5 mL). After stirring at 80 °C for 12 h, the mixture was quenched with saturated CH3COONa(aq) and extracted with dichloromethane (2 x 10 mL). The organic phase was dried over anhydrous MgSO4 and filtered. After removing the solvent from the filtrate, the mixture was purified by column chromatography on silica gel using petroleum ether / dichloromethane (3:1) as the eluent to give an orange solid (0.13 g, 84% yield).

[0166] (7) Compound 7 and 2-(3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile were reacted via the Knoevenagel reaction to yield the X3 acceptor material:

[0167]

[0168] A solution of compound 7 (1344.6 mg, 1 mmol) and 2-(3-oxo-2,3-dihydro-1H-inden-1-yl)malononitrile (1142 mg, 5 mmol) was added under nitrogen atmosphere with 5.0 mL of CHCl3 and 0.2 mL of pyridine. The reaction mixture was heated to reflux and stirred for 1.5 hours. After cooling to room temperature, the mixture was purified by column chromatography (silica gel) using CHCl3 as the eluent to give X2 (1273 mg, 81%) as a dark blue solid. 1H NMR (400MHz, CDCl3): δ7.86-7.80(d,J=7.6Hz,4H);7.61(t,J=7.6Hz,2H),7.00-6.94(m,4H),4.43(d,J=8.0Hz,4H),3.12(t,J=8.0Hz,4H),2 .09-2.03(m,2H),1.94-1.82(m,4H),1.45-1.37(m,4H),1.30-0.90(m, 38H), 0.90-0.83 (m, 6H), 0.81 (q, J = 7.4Hz, 6H), 0.72 (q, J = 7.5Hz, 6H).

[0169] Example 5

[0170] Fabrication of solar cells.

[0171] The indium tin oxide (ITO) glass used as the cathode (purchased from Shenzhen Nanbo Float Glass Co., Ltd.) was first cleaned with detergent, then ultrasonically cleaned with deionized water, acetone, and isopropanol in sequence. After drying, a 30nm thick PEDOT:PSS anode modification layer was spin-coated and dried at 150℃ for 15 minutes for later use.

[0172] 0.8 mg of the organic compound X3 prepared in Example 1 and 0.7 mg of the polymer donor material PM6 were mixed in 0.1 mL of chloroform to obtain a mixture, which was then spin-coated onto the above PEDOT:PSS layer. After drying, a light-harvesting active layer (effective area of ​​4 mm²) was obtained. 2 A 5 nm thick PDINN cathode modification layer was spin-coated onto the active layer under vacuum (absolute pressure 2 × 10⁻⁶). -5 A metallic Ag of approximately 80 nm is deposited by vapor deposition (Pa) as the cathode of a solar cell.

[0173] A simulated solar light source was used with an AM1.5 filter (SAN-EI ELECTRIC Co., Ltd. model XES-70S1), at 100mW / cm². 2Photocurrent density was measured under varying light intensity, calibrated using a standard monocrystalline silicon solar cell (purchased from VLSI Standards Inc.). Dark current density was also measured in the dark state. The resulting IV curves were measured using a Keithley 2450 Source-Measure Unit, controlled by a computer via LabVIEW software. The resulting IV curves are shown below. Figure 6 As shown, a battery capable of generating current can be formed.

[0174] Table 3 lists the performance parameters of the solar cells with different ratios of PM6 and X3 materials in the active layer.

[0175] Table 3: Performance parameters of PM6 and X3 batteries using two materials

[0176]

[0177] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. An organic compound, characterized in that, Its chemical structure is shown in Formula 1: Formula 1 Wherein, R1 is a C1~C12 alkyl group; X1, X2, X3, and X4 are each independently selected from H and halogen substituents; Ar is: R3 is selected from C1 to C20 alkyl groups; Each EG group is independently selected from any one of the following groups: 、 ； R4 is selected from hydrogen atoms and halogen substituents.

2. A method for preparing the organic compound as described in claim 1, characterized in that, The process includes the following: Compound X and compound A are coupled via a Stille reaction to yield compound B. The chemical reaction equation is as follows: ； Compound B undergoes a cyclization reaction with compound C to yield compound D, and the chemical reaction equation is as follows: ； Compound D undergoes a ring-closing reaction to yield compound E, and the chemical reaction equation is as follows: ； Compound E reacts with a haloalkane via a nucleophilic substitution reaction to yield compound F, wherein the haloalkane is R1X, and X is a halogen; the chemical reaction equation is as follows: ； Compound F is reacted with Vilsmeier-Haack to yield compound G, and the chemical reaction equation is as follows: ； The compounds G and EG were reacted via a Knoevenagel reaction to yield an organic compound as shown in Formula 1.

3. The method for preparing the organic compound according to claim 2, characterized in that, The Stille coupling reaction conditions are as follows: the solvent is toluene, the catalyst is tetrakis(triphenylphosphine)palladium, and the amount of catalyst added is 0.01% to 10% of the molar amount of compound A; the molar ratio of compound X to compound A is 1:2.2 to 3.5; and the reaction is carried out under reflux at 80°C to 110°C for 24 to 48 hours.

4. The method for preparing the organic compound according to claim 2, characterized in that, The conditions for the cyclization reaction are as follows: the solvent is N,N-dimethylformamide, the neutralizing agent is potassium carbonate, the molar ratio of the neutralizing agent to compound B is 1 to 20:1, and the reaction is carried out under reflux at 80°C to 120°C for 0.1 to 1 hour.

5. The method for preparing the organic compound according to claim 2, characterized in that, The conditions for the ring-closure reaction are as follows: the solvent is o-dichlorobenzene, the catalyst is triphenylphosphine, the molar ratio of the catalyst to compound C is 1:1 to 20, and the reaction is carried out under reflux at 150°C to 200°C for 12 hours. The conditions for the nucleophilic substitution reaction are as follows: N,N-dimethylformamide is used as the solvent, potassium hydroxide is used as the neutralizing agent, the molar ratio of the haloalkane to compound E is 3 to 6:1, and the reaction is carried out under reflux at 80°C to 100°C for 15 to 24 hours. The conditions for the Vilsmeier-Haack reaction are as follows: the solvent is N,N-dimethylformamide, phosphorus oxychloride is the formylation reagent, the molar ratio of compound E to phosphorus oxychloride is 1:15-25, and the reaction is carried out under reflux at 80℃-105℃ for 8-12 hours. The conditions for the Knoevenagel reaction are as follows: chloroform as solvent, pyridine as acid-binding agent, and the molar ratio of compound E to EG is 1:5 to 12; the reaction is carried out under reflux at 60°C to 70°C for 12 to 16 hours.

6. An organic solar cell acceptor material, characterized in that, Including the organic compounds as described in claim 1.

7. A solar cell, characterized in that, It includes a photoelectric conversion active layer, which comprises an organic solar cell electron donor material and an organic solar cell acceptor material as described in claim 6.

8. The solar cell according to claim 7, characterized in that, The photoelectric conversion active layer also includes an organic solar cell electron donor material, which includes one or more of PM6, D18, PBDB-T and PTB7-Th.

9. The solar cell according to claim 8, characterized in that, The molar ratio of the organic solar cell acceptor material to the organic solar cell electron donor material is 1 to 1.5:1.

Images